Cockroaches have long been recognized as pests of economic and aesthetic concern. They have become increasingly important in public health and veterinary medicine. For example, it is well known that cockroaches regularly move between sewers and human food materials. As a result, cockroaches acquire, carry, and transfer pathogens either mechanically or in their digestive system. This problem is especially evident in public housing, where cockroach populations are large and problems such as salmonellosis are particularly prevalent. Cockroaches also serve as intermediate hosts for the spiny-headed worms that infect the small intestines of vertebrates. Hypersensitivity to cockroaches is particularly common among inner-city residents and workers in entomological laboratories where both intensity and duration of exposure are high. Therefore, the need for effective suppression of cockroach populations to alleviate health-related problems (as well as aesthetic concerns) is self-evident.
The need to suppress cockroach populations has resulted in the use of large amounts of pesticides in urban environments. However, use of broad spectrum toxins for insect control is a serious environmental risk. In addition, broad spectrum toxins foster insecticide resistance and make subsequent insect control more difficult. Accordingly, there is a continuing need for the development of safe, effective, and environmentally compatible insect control techniques.
In recent years, compounds known as pheromones have been recognized as useful components of a successful pest control program. A pheromone is generally defined as a chemical substance secreted by living organisms, including insects, to convey information or produce a specific response in other individuals of the same species. Sex pheromones typically take the form of a complex, volatile blend of compounds which is, for example, excreted during the mating cycle. As such, sex pheromones often serve as "attractants"; that is, the pheromone attracts insects of the same species to the location of the pheromone emission.
There are several pheromones used by cockroaches, including those used at a distance (volatile), at close range (mostly male tergal secretions), and by contact only (cuticular components). However, only long distance pheromones are practically useful in pest control programs. To date, only three structures having attractant activity relative to test cockroaches have been characterized. These attractants are generally known as periplanone B, periplanone A, and periplanone J, respectively. The pheromonal activity of these compounds is, however, restricted to cockroaches of the genera Periplaneta and Blatta.
Attractants for many other cockroaches have not been developed. One cockroach species for which no structure having pheromonal activity has been synthesized is Supella longipalpa, also known as the "brown-banded cockroach." The brown-banded cockroach, however, poses an ever-increasing pest control problem. First observed in the continental United States in 1903, brown-banded cockroaches have been collected throughout the United States in recent years and have become a major pest in many regions of the southern United States. In the Northeast, brown-banded cockroach infestations are most common in areas where pesticide usage is restricted, e.g., schools, hospitals, nursing homes. They are also an important pest in tropical and subtropical regions. Therefore, an object of this invention is to provide chemical compounds that exhibit sex attractant activity relative to the brown-banded cockroach.